Automatic air-brake mechanism



No. 622,020. Patented Mar. 28, I899. S. W. ROBINSON 81. E. A. HITCHCOOK.

AUTOMATIC AIR BRAKE MECHANISM.

(Application filed Nov. 4, 1897.)

(No Model.)

WITNESSES:

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UNTTED STATES PATENT @rrrcn.

STILLMAN W. ROBINSON AND EMBURY A. HITOHOOOK, on COLUMBUS,

OHIO.

AUTOMATIC AIR-BRAKE MECHANISM.

SPECIFICATION forming part of Letters Patent No. 622,020, dated March28, 1899. Application filed November 4, 1897. Serial No. 657,444. 7 (N0model.)

relation to new attachments for a well-known form of triple valve.

The objects of our invention are to provide the triple valve withimproved additional mechanism and attachments whereby, in addition tothe usual maximum air-pressure in the brake-cylinder necessary forservice stops, the desired pressure for what are known as emergencystops may be readily and positively attained; to accomplish the aboveobject in a simple and comparatively inexpensive manner and by the aidof comparatively few new parts; to so construct and arrange ourattachments as not to interfere with the usual or ordinary operation ofthe triple-valve mechanism during service stops, and to utilize, inconnection with the additional or superadded brake-cylinder pressurewhich we employ in the manner hereinafter described for emergency stops,the usual train-pipe pressure which is ordinarily employed for servicestops; to so construct and arrange the parts of our improved attachmentsas to admit of their being readily used in connection with an ordinaryair-brake mechanism with comparatively slight additions to the triplevalve, the details of construction and arrangement of parts of whichwill be more fully pointed out hereinafter.

These objects We accomplish in the manner illustrated in theaccompanying drawings, in which Figure 1 is a longitudinal section of aknown form of triple-valve brake-cylinder and auxiliary reservoir,showing our improvements connected therewith and for the sake ofclearness showing the chambers and passages of the triple valve in thesame plane. Fig. 2 is a detail view in perspective of a valve which weemploy in the manner hereinafter described, and Fig. 3 is an enlargedcentral longitudinal section of the valve, shown in Fig.2. Similarnumerals refer to similar parts throughout the several views.

The general form of triple valve herein shown is of a character too wellknown to 11ecessitate a detailed description of its construction andoperation, but the same consist of the following parts, arranged ashereinafter set forth.

1 represents the triple-"alve casing or body, in which is mounted inthewell-known manner a piston 2, the latter being arranged in theenlarged mouth of a horizontal passage 3 and having a valve-controllingarm 4, which extends into said passage and controls the movement ofseparated slide-valves 5 and 6, which are adapted to close and openports 7, 8, and 9 in the bottom of said passage 3. The ports 8 and 9communicate with a lower passage 10, which leads in the usual mannerinto the,brake-cylinder 11, while the port 7 communicates with theatmosphere. In the outer recessed side of the piston-head 2 is inserteda piston 12, having a central outwardly-extending stem 13, which isadapted to bear and slide in the body of the triple valve. The

piston-head 12 is provided with a small opening therethrough, which isindicated at 14. The outer end of the piston-stem 13 projects within anend chamber 15, as shown.

16 represents a charging-groove which is adapted to form in the usualmanner communication between the inner end of the passage 3 and thespace on the outer side of the piston 2. The outer end of thepiston-stem 13 is normally in close proximity to the inner side of thearm 17 of a spring-actuated valve 18, which normally closes the mouth ofa passage 19.

Through the medium of a passage 20 the train air-pipe 21 communicateswith the chamber 15 and also with the mouth of the passage 8 in front ofthe piston 2.

The outer end of central stem 25, which extends within a passage 26 andis normally retained in close proximity to the end of a valve 27, whichclosesa port or valve opening between the passage 26 and a chamber 28.This chamber 28 comm unicates, as shown, through a passage 29 with achamber 30 at the end of the passage 3. Through the medium of a suitablepipe connection 31 the chamber 30 is connected with the usual auxiliaryairreservoir 32. The valve 27 is provided with a stem extension Thepassage 26 leads, as indicated in dotted lines, through a checkvalve26"" into the chamber 10.

The above-described construction of the triple valve is well known andhas been described briefiy for the purpose of illustrating ourimprovements in connection therewith, said improvements being describedas follows: The chamber 28 is provided with a threaded opening 3%, intowhich is ordinarily introduced a plug into which the arm 33 of the valve27 has commonly extended. In place of inserting a plug in said opening3t we connect therewith a tubular casing extension or neck 35, withinthe inner portion of which is fitted an open guide-ring 36, throughwhich the valve-stem is adapted to slide, said valve-stem being providedin the usual manner with a coiled spring 37, one end of which bearsagainst the valve and the remaining end of which bearsagainsttheguidering 36. Within the extension 35 we provide a valve-seat 38, whichis normally closed by a spring or gravity actuated valve 39, the stem 40of which is adapted to fit and slide within a central recess 41 of aplug 42, which closes the outer end of the casing extension 35.

The preferable construction of the valve 39 and its stem 40 is moreclearly shown in Figs. 2 and 3 ot the drawings. Within the stem portionl of the valve we provide a chamber 39, the outer end of which is closedby a detachable plug 39, said plug being formed with a centralguide-socket, (indicated at 39.) The forward end of the chamber 39 hasleadin g therefrom a smaller passage or extension of said chamber,which, as shown, extends longitudinally through the head of the valveand which is indicated at 39. Vithin the chamber 39 we provide acheck-valve 40, which is adapted by pressure of a spring 40 toclosecommunication between the chamber 39 and the passage 39. The stem40 of the check-valve 40, about which is coiled the spring 40', isadapted to fit and slide within the guide-socket 39 of the plug 39". Asshown at 4:0, we provide the valve-stem 40 with oppositely-locatedports, which communicate with the chamber 39*. On the outer side of thevalve 39 we connect with the casing extension 35 a pipe t3, which leadsto a conveniently-located air-reservoir 4A, the latter being of acomparatively small size and being adapted in the manner hereinafterdescribed to contain additional air of train-pipe pressure.

In order to properly charge for use the various compartments, passages,and reservoirs hereinbefore described, the compressed air from thetrain-pipe leads through the passage 20 into the chamber 15 and into themouth of the passage 3. From the latter point the air passes through thecharging-groove 19, through said passage 3 into the chamber 30, thencethrough the passage 29, chamber 28, and into the extension 35. The airthus directed into said. extension passes through the valve-passage 39of the valve 39 and, opening the valve 40", the air thus directed intothe passage 39 escapes through the openings 40, from which points theair passes through the pipe 43 into the reservoir 4-1:. It is ob viousthat when the pressure in said reservoir 4A and pipe 43 becomessubstantially equal to the pressure in the chamber 28 the comparativelyweak spring of the valve 4:0 will serve to close thelatter. From thechamber 30 the air passes in the usual manner through the pipe 31. intothe usual auxiliary reservoir In the above manner the airpressure in thevarious compartments and passages mentioned is substantially equalized.

Although ourinvention does not pertain to the manner of producing whatis known as a service application, we will in order to more clearlyillustrate the use of our device describe in a general way the usualmanner of applying the air for service stops. In producing this serviceapplication the pressure in the train-pipe is reduced in the usualmannor a comparatively small amount, which results in lowering thepressure accordingly in the chamber 15 and in the passages leadingthereto. The train-pipe pressure being thus reduced, it is obvious thatthe greater pres sure of air in the auxiliary reservoir must result inforcing the piston 2 outward, which in the usual manner opens the port 9and provides a communication between the passages 3 and 10, causing theair to flow to the brakecylinder 11 and exert its pressure upon theusual spring-actuated piston of the latter. Vhen the pressure in theauxiliary reservoir is in this manner sufficiently reduced untilslightly less than that in the chamber 15, the piston 2 partiallyreturns to the position shown in the drawings, closing the port 9 andleaving the parts in position for f u rtherservice applications inincreasing pressures in the brake-cylinder.

It is well known that in order to produce a quick stop of the train, orwhat is generally termed an emergency stop, it becomes necessary toapply quickly a greater air-pressure to the brake-cylinder than thatordinarily attained in the service application. In the latterapplication the movement of the piston 2 is not accomplished withsufficient speed or quickness to prevent the air which is between thepistons 2 and 12 escaping through the vent 14. of the latter, thusadmitting of the movement of the piston 2, while the piston 12 issubstantially stationary. In an emergency stop, however, the operatorreduces the pressure in the train-pipe to such a degree and with suchrapidity as to result in the piston 2 being forced outwardly at suchspeed as to cause the air back of the piston 12 to carry the latterforward, no time for the escape of the air through the vent 14 beingallowed. By this forward movement of the piston-stem 13 a contact of thelatter with the arm 17 of the valve 13 is produced, which opens thepassage 19 to communication with the chamber 15. The pressure of air inthe passage 19 forces the piston 24 back in the chamber 22, resultingnot only in opening the port 23,and thereby providing an escape for theair, but in opening the spring-actuated valve 27 through contacttherewith of the stem 25. Through the opening of the valve 27 theairpressure from the auxiliary reservoir and which is equal in thechamber 28 is directed into the passage 26 and thencethrough the valve26 and passage 10 to the brake-cylinder. This flow of air, which isprovided by opening. the valve 27-, is thus produced in addition to theflow of air through the port 9, the two currents being joined in thepassage 10. The above-described known emergency application, althoughproducing a certain pressure in the brake-cylinder, is not regarded assufficientfor emergency stops, and in order to remedy this difficulty wehave provided the following additional operation: lVhen the valve 27 isopened, its stem 33 comes into contact with the spring-actuated valve39, thereby providing through the extension 35 and pipe 43 acommunication between the additional reservoir 44 and the passage 26,and a consequent increase in the amount of air which is directed intothe brakecylindcr, resulting in a decided increase of air-pressuretherein.

As indicated in the drawings, the additional reservoir 44 is small ascompared with the auxiliary reservoir. The small size of this additionalreservoir, together with the comparatively large outlet therefrom whichis afforded by the opening of the valve 39 and by the passage of theextension, must result, as will readily be seen, in a rapid reduction ofthe air-pressure in the reservoir 44 in comparison with the reduction inthe reservoir 32, inasmuch as the passage 29, through which the greaterportion of the air from said auxiliary reservoir must pass to theemergency channel 26, is limited in size. In this manner the additionalair supplied by the reservoir 44 is quickly transmitted to thebrakecylinder,where, in conjunction with the usual air-supply from theauxiliary reservoir, it raises the air-pressure within saidbrake-cylinder to the required amount for the emergency application ofthe brake. Owing to the stiffness or rigidity of the spring which isabout the valve-stem 40 the air which returns from the brake-cylinderinto the extension 35 immediately after the piston of thebrake-cylinderhas operated hasnot sufficient pressure to open the valve39, thus preventing undesirable rapidity in the reduction of thepressure in the brake-cylinder which might otherwise be caused by a toorapid return of the air therefrom to the reservoir 44. In making thisreturn from the brake-cylinder or other parts of the brake system air isgradually returned to the reservoir 44 by entering the passage 39,opening the valve 40, which is controlled by a comparatively lightspring, and entering the passage 39, from which the air escapes throughthe ports 40 and thence through the pipe 43 to said reservoir 44;

In case it should be found that a comparatively rapid return of the airto the reservoir 44 is not detrimental to the proper operation of thebrake-cylinder piston it is obvious that the valve 39 and its stem 40may be formed without the central chamber 39 and passage 39 and acomparatively light spring SllbStlr tuted for the otherwise stiif springwhich actuates said valve 39.

It will be observed that the new parts necessary to produce ourattachments are exceedingly few in number and simple of construction. Inthis connection attention is called to the fact that the valve 39 may besubstantially a duplicate of the valve 26, which .is ordinarilyemployed, and that the plug 42 is simply substituted for the plugusually employed in the threaded opening 34 or in an opening oppositethe valve 26. (Not herein shown.)

From the construction and operation of our device it will be seen thatsimple, reliable, and effective means are provided for producing in thebrake-cylinder the desired increase in air-pressure in making emergencystops, the same exceeding the maximum in service stops, and that thesemeans may be readily adapted for use in conjunction with the ordinaryair-brake mechanism.

Having now fully described our'invention, what we claim, and desire tosecure by Letters Patent, is p 1. In an automatic air-brake system, thecombination with a triple-valve body provided with chambers and passageswhich are normally in communication with the train-pipe and an auxiliaryreservoir, a passage 26 1O communicating with the brake-cylinder, avalve 27 normally cutting off communication between the passage 26 whichleads to the brake cylinder and a chamber 28 which normally communicateswith the train-pipe, of a supplemental air-reservoir 44 and a valve 39normally cutting off communication with the supplemental reservoir andopening only in the case of a sudden reduction of pressure in thetrain-pipe, said supplementalreservoir having no communication with theauxiliary reservoir excepting through a passage or passages of thetriple-valve body and means whereby the opening operation of the valve27 opens communication between said supplemental reservoir and thepassages leading to the brakecylinder, substantially as specified.

2. In an automatic air-brake system, the combination with a triple-valvebody provided with chambers and passages which are normally incommunication with the train-pipe and an auxiliary reservoir, one ofsaid passages having a port communicating with a passage leading to thebrake-cylinder, said port adapted to be opened by the pressure of airfrom the auxiliary reservoir and a valve 27 normally cutting offcommunication between a passage 26 which leads to the brakecylinder anda chamber 28 which normally communicates with the train-pipe, of a neckextension 35 of said triple-valve body, a spring-actuated valve 39normally closed against the valve-seat in said extension, a supplement-al air-reservoir A connected with said extension on the outer side ofsaid valve 39 and means whereby the opening of the valve 27 isaccomplished by the sudden reduction of the air-pressure in thetrain-pipe and whereby the opening of said valve 27 also results in theopening of the valve 39, substantially as and for the purpose specified.

3. In an automatic air-brake system, the

combination with a triple-valve body provided with chambers and passageswhich are 11ermally in connection with the train-pipe and an auxiliaryreservoir, the passage 26 10 communicating with the brake-cylinder and avalve 27 normally cutting off communication between the passage 26 whichleads to the brake-cylinder and a chamber 28 which normally communicateswith the train-pipe, of a neck extension 35 in said triple-valve body, aspring-actuated valve 39 normally closed against the valve-seat in saidextension, a chamber within said valve-body, a-valve-controlled opening39 leading thereto, ports 40 leading from said internal chamber, asupplemental air-reservoir connected with said extension and meanswhereby the opening of the valve 27 is accomplished by the suddenreduction of the air-pressure in the train-pipe and means whereby theopening of said valve 27 also results in the opening of the valve 39,substantially as and for the purpose specified.

STILLMAN \V. ROBINSON. EMBURY A. IIITOIICOCK. In presence of- A. L.PnELrs, EDWARD M. TAYLOR.

